A) Field of the Invention
The present invention relates to a connection piece for connecting a housing of a drive unit to the housing of a compressor element.
Such connection pieces are used in compressor aggregates for connecting the housing (mostly made of cast metal) of a compressor element with the housing in which a drive unit of the compressor element is situated, for example, the housing of a motor. Due to the particular constructions of such housings, these housings cannot be manufactured as one whole unit.
B) Related Art
Typically, the coupling between the shaft or shafts of the rotor or rotors of the compressor element and the outgoing shaft or shafts of the drive unit is situated in the connection piece. Moreover, a gear-wheel transmission or another coupling transformer may also be integrated in the connection piece.
Compressor aggregates create a lot of noise. In order to restrict the noise level, vibration dampers are used for insulating the aggregate from the ground, and the framework is equipped with noise-restricting material. The channels through which ventilation air is sucked in are also acoustically treated.
Although these techniques already achieve a considerable noise dampening, the noise level of the compressor aggregate is still rather high.
In an effort to further reduce this noise level, research has been made which demonstrates that considerable noise energy is created in the compressor element. Because of the structural features of the whole aggregate, such noise energy is transformed into undesired vibrations and noise.
In particular, resonant frequencies of the structure of the aggregate are evoked by the pulsation frequencies of this compressor element, which leads to the radiation of superfluous noise energy.
It was noted that especially the connection piece between the housings of the compressor element and the drive unit is responsible for noise emission as well as transmission of vibrations and noise from the compressor element to the motor and to the support points of the connection piece.